No power to Blue Breaker

[Internal K-Dart]

Hi everyone,

This is my first post on the forum, though I've been reading them for a little while now. It has been such a valuable resource to me as a beginner pedal builder.

When I was in high school (20 years ago), I tried to build an MXR Blue Box from a schematic I found online and never got it to work. It has always haunted me that I gave up. At some point recently, I learned that you could buy PCBs and I decided it was time to right the circuit-building wrongs of my past. I finished my first two builds this week, the Crackle Jack and Amentum Boost which came together successfully aside from some silly mistakes (forgot to socket the transistor on one, d'oh). Lurking on the forums here and scouring youtube (the dk pedals channel, etc.) has been incredibly enlightening and really helped prepare me to build these pedals successfully.

When I "finished" my third, a Blue Breaker, I was feeling confident but, alas, I've been humbled by the pedal gods. The central issue is that I am getting no power whatsoever.

WHAT WORKS:
--the clean bypass signal works fine when the pedal is off

WHAT DOESN'T WORK:
--When engaged, the LED does not light up

--No guitar signal when the circuit is "on"

WHAT I HAVE TRIED:
There was a prior thread about no power w/ a Blue Breaker but it seems like a different issue and with no resolution:
https://forum.pedalpcb.com/threads/no-power-on-blue-breaker-build.8095/

I checked out the Troubleshooting 101 thread and followed the instructions to check the voltage with a multimeter.
https://forum.pedalpcb.com/threads/troubleshooting-101.9028/

When I checked the voltage, I got no voltage coming from the + tip of the power jack. I tried checking the voltage on the Amentum Boost pedal since I know it works just to make sure I was doing it correctly and I got 9 volts on the + tip of the power jack. So, I soldered in a new power jack thinking it was just a part malfunction and I was all set. Tried it again and still no power. I desoldered the + and - leads and tested just the power jack with alligator jumpers to the multimeter and got 9 volts. Additionally, I tested a brand new power jack (got 9 volts on the multimeter) and then connected alligator clips from the desoldered + and - leads to the new power jack and tried powering it up. No power, as expected. It seems like I've narrowed it down to some kind of workmanship issue on the board (though correct me if I'm wrong). I previously re-flowed the solder joints for the + and - leads after first discovering that there was no power. (I also thoroughly scrubbed the board with a toothbrush and 99% isopropyl before housing it.)

I tried looking at the schematic too but I have no EE background so I figured it was better to come to the experts instead of guessing what I'm looking at.

I followed the same process as the previous, successful builds so I am at a loss as to where I've gone wrong this time.

Any ideas of what I should try next? Am I overlooking something really obvious?

I've taken several pictures but let me know if I've missed showing anything that could be helpful to determine the issue.

Thanks for your help!

 

[carlinb17]

So correct me if I'm wrong but you are now getting 9v on the + pad of the pcb correct? If so do you have a voltage on both sides of the 1N5817 protection diode?

 

[Robert]

Make sure the red wire going to your LED isn't touching the metal bezel. Can't see it in the pic, but if it's leaning against the side that could be the culprit.

 

[Internal K-Dart]

Thanks for your response. Sorry for being unclear. I only get 9v directly from the power jack. Nothing on the + pad on the board.

 

[Internal K-Dart]

Make sure the red wire going to your LED isn't touching the metal bezel. Can't see it in the pic, but if it's leaning against the side that could be the culprit.

View attachment 34659

Thanks, that's a good suggestion. The bezel is actually plastic (painted to look metallic) but I did take the LED out of it and it doesn't seem like that is the problem. Definitely something I'll keep an eye on in the future because I did a pretty bad job this time soldering the LED.

 

[Robert]

If I understand correctly, you measure 9V on the jack only when the PCB is disconnected?

If the 9V is dropping when the PCB is connected to the DC jack there is a short of some sort. You can pull the IC out of the socket to ensure that's not the issue, outside of that you're looking for a solder splash or bridge of some sort.

 

[Internal K-Dart]

If I understand correctly, you measure 9V on the jack only when the PCB is disconnected?

If the 9V is dropping when the PCB is connected to the DC jack there is a short of some sort. You can pull the IC out of the socket to ensure that's not the issue, outside of that you're looking for a solder splash or bridge of some sort.

Yes, that's right. Thank you that gives me some guidance. I'll pull the IC and scrutinize the board when I get the chance and report back.

 

[carlinb17]

It would also be good to check your footswitch for bridges under the board

 

[Internal K-Dart]

Robert and carlinb17, thanks for your help. Even though I thought I had thoroughly cleaned the board I found a bit of residue that I think was the culprit. I gave the board another really good clean and it fired up correctly.

It would also be good to check your footswitch for bridges under the board

When I read this, this was a lightbulb moment. I hadn't thought about potentially flooding the switch with solder under the board and causing unseen bridges. I'll definitely keep this in mind for future builds. Thanks for the tip